Size-dependent role of gold in g-C3N4/BiOBr/Au system for photocatalytic CO2 reduction and dye degradation

Surface plasmon resonance (SPR) and Z-scheme bridge are the most important roles of noble metal nanoparticles for photocatalysis. In this study, the size-dependent role of gold (Au) in Au/g-C3N4/BiOBr system was studied for photocatalytic CO2 reduction and dye degradation. The results revealed that big Au nanoparticles mainly displayed Z-scheme bridge role, and g-C3N4/BiOBr/Au-B showed higher photocatalytic activity than g-C3N4/BiOBr under 380nm monochromatic light irradiation. Small Au nanoparticles mainly displayed SPR role, and g-C3N4/BiOBr/Au-S showed higher photocatalytic activity than g-C3N4/BiOBr under 550nm monochromatic light irradiation. The size-dependent role of Au nanoparticles for photocatalytic system should be due to the SPR effect of small Au nanoparticles and electron transfer center of big Au nanoparticles. This finding can guide us to prepare high photocatalytic activity noble metal loaded photocatalysts.